Journal of High Energy Physics

, 2017:38 | Cite as

Collinear limits beyond the leading order from the scattering equations

  • Dhritiman Nandan
  • Jan Plefka
  • Wadim Wormsbecher
Open Access
Regular Article - Theoretical Physics


The structure of tree-level scattering amplitudes for collinear massless bosons is studied beyond their leading splitting function behavior. These near-collinear limits at sub-leading order are best studied using the Cachazo-He-Yuan (CHY) formulation of the S-matrix based on the scattering equations. We compute the collinear limits for gluons, gravitons and scalars. It is shown that the CHY integrand for an n-particle gluon scattering amplitude in the collinear limit at sub-leading order is expressed as a convolution of an (n − 1)-particle gluon integrand and a collinear kernel integrand, which is universal. Our representation is shown to obey recently proposed amplitude relations in which the collinear gluons of same helicity are replaced by a single graviton. Finally, we extend our analysis to effective field theories and study the collinear limit of the non-linear sigma model, Einstein-Maxwell-Scalar and Yang-Mills-Scalar theory.


Scattering Amplitudes Effective field theories 


Open Access

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Copyright information

© The Author(s) 2017

Authors and Affiliations

  • Dhritiman Nandan
    • 1
  • Jan Plefka
    • 1
  • Wadim Wormsbecher
    • 1
  1. 1.Institut für Physik and IRIS AdlershofHumboldt-Universität zu BerlinBerlinGermany

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